Influence of Porous Dressings Based on Butyric-Acetic Chitin Co-Polymer on Biological Processes In Vitro and In Vivo

Abstract

In spite of intensively conducted research allowing for the development of more and more advanced wound dressing materials, there is still a need for dressings that stimulate not only reparative and regenerative processes, but also have a positive effect on infected and/or difficult-to-heal wounds. Porous dressing materials based on butyric-acetic chitin co-polyester containing 90% of butyryl and 10% of acetyl groups (BAC 90/10) can also be included in the group mentioned above. Two types of dressings were obtained by the salt leaching method, i.e. a porous sponge Medisorb R and Medisorb Ag with an antibacterial additive. The aim of the study was to evaluate biological effects of porous Medisorb R and Medisorb Ag dressings under in vitro and in vivo conditions. In an in vitro biodegradation test, no mass loss of Medisorb R dressing was observed within 14 days of incubation in physiological fluids at 37 °C. However, on the basis of the FTIR (Fourier Transform Infrared Spectroscopy) tests, surface degradation of Medisorb R dressing was observed. Additionally, the antibacterial activity of the porous Medisorb Ag dressing containing microsilver as an antibacterial additive was confirmed. The in vivo studies included inflammatory activity, skin irritation and sensitisation tests, as well an assessment of local effect after contact with subcutaneous tissue up to 6 months and skin wounds up to 21 days. In the in vivo tests, the dressings exhibited neither effects of skin irritation nor sensitisation. Under macroscopic examination, in full thickness defects of subcutaneous tissue and skin, the dressings caused wound healing with no inflammation, undergoing the most gradual biodegradation between weeks 4 and 8, and the observed differences were statistically significant. In the histological assessment, a weakened, limited inflammatory process associated with degradation of the material has been observed. The process of skin wound healing under Medisorb R dressing in the early period was accelerated compared to that observed in the control group with a gauze dressing.

Modulating the Physicochemical Properties of Chitin and Chitosan as a Method of Obtaining New Biological Properties of Biodegradable Materials

“…The dressing shortens and weakens the exudative phase, drains the wound and accelerates the productive phase. The epithelialization process under the butyryl-acetyl chitin co-polyester was completed faster compared to the control sample [37].…”

“…It confirmed the sample surface degradation, which was connected to the hydrolysis of ester BAC 90/10 groups. In the in vivo tests, the dressings under macroscopic examination, in full thickness defects of subcutaneous tissue and skin caused wound healing with no inflammation, undergoing the most gradual biodegradation between weeks 4 and 8, and the observed differences were statistically significant [37].…”

Characteristic Features of Wound Dressings Based on Butyric-Acetic Chitin Copolyesters—Results of Clinical Trials

“…For manufacturing of the Medisorb R Membrane and Medisorb R Ag, the method using NaCl as porophor and 3% BAC 90:10 solution in ethanol was applied. The exact manufacturing methods of the dressings and their full physio-chemical and biological characteristics (in vivo and in vitro tests on animals) are presented in other papers [44][45][46].…”

“…The dressings used within the clinical trials were tested in in vitro conditions where it was demonstrated that the Medisorb R dressings degrade when under the influence of the serum/plasma enzyme and that Medisorb R Ag shows bacteriostatic and bactericidal activity. There were also tests regarding irritation after multiple applications on skin, sensitization activities, healing-in process after intradermal application for up to 6 months, and the influence of the dressing on healing of skin loss of full thickness for up to 21 days [45]. It was concluded that porous Medisorb R and Medisorb R Ag dressings are biocompatible and safe materials.…”

“…The tested materials had a positive effect on regeneration of damaged skin tissue. Medisorb R Ag, which contains silver as an anti-bacterial agent, showed significant activity against Staphylococcus aureus and Klebsiella pneumoniae [45].…”